"This article discusses the methodology of a recently published British randomized clinical trial comparing chiropractic and physiotherapy as treatments for low back pain.

The authors base their main conclusions on a difference shown by the Oswestry pain questionnaire 2 yr after randomization, when data of only 26% of the patients were available. This might have led to an overestimation, because it appears that the difference in Oswestry scores is much larger for patients included early in the study. It may also be doubted whether the magnitude of the effect reported really indicates a clinically significant difference between the interventions.

In addition to allocated intervention, the groups also differ in duration of treatment, number of sessions, level of experience of the therapist, and health care setting.

The results are difficult to extrapolate, because only a small portion of the eligible patients participated, and chiropractic seems to be clearly superior only in the subgroup originally presenting to a chiropractic clinic.

We conclude that it is premature to draw conclusions about the long-term effectiveness of chiropractic based on the results of this study alone."